The governor of Okinawa has approved controversial plans to relocate a US Marine base to a less populous area – but said he would keep pressing to move the base off the of the Japanese island altogether.

The nod from Okinawa, long a reluctant host to the bulk of US military forces in Japan, is an achievement for Prime Minister Shinzo Abe, who has promised a more robust military and tighter security ties with the US amid escalating tensions with China.

Sceptics, however, said it remained far from clear whether the relocation – stalled since the move was first agreed upon by Washington and Tokyo in 1996 – would actually take place given persistent opposition from Okinawa residents, many of whom associate the US bases with crime, pollution and noise.

The approval came a day after Mr Abe visited Tokyo’s Yasukuni Shrine, which is seen in parts of Asia as a symbol of Japan’s past militarism. His trip infuriated China and South Korea, and prompted concern from in Washington about deteriorating ties between the Asian neighbours.

Hirokazu Nakaima, the Governor of Okinawa, told a news conference he had approved a central government request for a landfill project at the new site, on the Henoko coast near the town of Nago. His approval for that project, required by law and a first step to building the replacement facility, was the last procedural barrier to eventually replacing the US Marine Corps’ Air Station Futenma in the crowded town of Ginowan. “The government has recently met our requests in compiling a plan to reinvigorate Okinawa. We felt that the Abe government’s regard for Okinawa is higher than any previous governments,” Mr Nakaima said.

However, he added that he still believed the quickest way to relocate Futenma air base would be to move it to an existing facility with runways outside Okinawa.

About 2,000 people gathered in front of the island’s government building to protest against Mr Nakaima’s decision, with a few hundred of them staging a sit-in at the lobby, the Jiji news agency said. The US and Japan agreed in 1996 to close the Futenma base but plans for a replacement stalled in the face of opposition in Okinawa, which hosts more than half of the US force in Japan, which totals about 38,000 military personnel, 43,000 dependents and 5,000 civilian employees. Okinawa was occupied by the US after Japan’s defeat in the Second World War until 1972.

Japan’s ties with the US were strained when then-Prime Minister, Yukio Hatoyama, who took office in 2009, sought to keep a campaign promise to move the US base off Okinawa. Futenma has been a lightning rod for criticism because of its location in a densely populated area. Activists living in tents have been staging a protest near the site of the proposed Henoko base for almost 10 years and have promised demonstrations if Nakaima approves construction.

An election for the mayor of Nago next month could prove problematic if the incumbent Susumu Inamine – who opposes the plan – is re-elected, while the central government could face a dilemma if demonstrators try to block construction. “There are so many potential wild cards, so much that has to be done, that every small decision moves the process forward but by no means guarantees a final conclusion,” said Brad Glosserman, of Pacific Forum CSIS, a Hawaii-based think-tank.

In April, the US and Japan unveiled plans to close Futenma as early as 2022. Mr Abe said the government would study whether that plan could be accelerated and would begin negotiating a deal with Washington that could allow for more local oversight of environmental issues at US bases. That would address Mr Nakaima’s call to revise the bilateral Status of Forces agreement that has applied to the US military in Japan since 1960 but has never been officially revised.

Mr Abe’s government has set aside ¥348bn for Okinawa’s economic development for the year from April – 15.3 per cent more than this year.